Infectious RNA without capsid:

Explanation

The answer is B) viroid. A viroid is a small, infectious RNA molecule that does not have a protein coat (capsid). Viroids are the smallest known infectious agents. They are able to replicate in plants, but they cannot infect animals or humans. A virus is a small, infectious agent that can replicate only inside the living cells of an organism. Viruses can be classified into 3 groups. A prion is a misfolded protein that can transmit its misfoldedness to normal variants of the same protein and trigger cellular death. A virion is a complete virus particle, including the nucleic acid (DNA or RNA) and the protein coat.